This research seeks systematically to explore and characterize the mechanical and chemical processes involved in the degradation of blood during flow through artificial organs. The work involves a two-pronged study of surface damage and shear damage to blood. Because of the overall complexity of the problem, certain components such as red cells, platelets and certain proteins have been picked for study. Current studies involve: 1. Measurement of the adhesion of blood cells (especially red cells) to a variety of foreign surfaces with protein adsorbtion and/or permanently bonded aldehyde coatings using a flow channel technique. 2. Measurement of the effect of temperature on red cell membrane deformability. 3. Investigation of hemolytic and sub-hemolytic alterations (e.g., change in ionic flux, glucose metabolism and ATP concentration; loss of membrane constituents) induced by laminar and turbulent shear flow in tube and Couette flow devices. 4. Investigation of the effect of flow on the breakdown of prothrombin in the presence of the enzyme-catalyst thrombin.